PySubitles supports reading and writing subtitle files (currently SRT and SUB), splitting and merging subtitles, as well as performing time shifting, among others. It was originally created by Jan Gerber (~j) at oil21 org and this is its Launchpad home.
Jan is welcome to reclaim the ownership for the project, it has only been created to make it easier to publish patches :-)

  >>> from subtitles import Subtitle
  >>> s = Subtitle()
  >>> s.loadSrtFile(path_to_srt)
  >>> s.shift(1000) # mseconds
  >>> srt = s.toSrt() #unicode string in srt format

  >>> s['3']
  {'in': '00:00:05,800', out: '00:00:10,120',
  text: 'The last 100 years have been\na story of resistance on'}

  >>> text = unicode(s) # just the text without time and running number